<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>grid</title>
    <style>
        .Grid {
            display: flex;
            width: 200px;
            height: 200px;
            border: 1px solid #ccc;
        }

        .Grid-cell {
            flex: 1;
        }

        .Grid-cell.u-full {
            flex: 0 0 100%;
        }

        .Grid-cell.u-1of2 {
            flex: 0 0 50%;
        }

        .Grid-cell.u-1of3 {
            flex: 0 0 33.3333%;
        }

        .Grid-cell.u-1of4 {
            flex: 0 0 25%;
        }
    </style>
</head>
<body>
<div class="Grid">
    <div class="Grid-cell u-1of4">...</div>
    <div class="Grid-cell ">...</div>
    <div class="Grid-cell u-1of3">...</div>
</div>
</body>
</html>